UNIVERSITY    OF   CALIFORNIA 

COLLEGE    OF    AGRICULTURE 
AGRICULTURAL   EXPERIMENT  STATION 

CIRCULAR  No.  229 
November,  1921 

CORDON  PRUNING 

By  FREDERIC  T.  BIOLETTI 


INTRODUCTION 

Nearly  all  systems  of  vine  pruning  can  be  placed  in  one  of  two 
groups :  the  head  systems  and  the  cordon  systems.  In  the  former  all 
arms  or  short  ramifications  of  the  vine  arise  from  the  top  of  a  com- 
paratively short  vertical  trunk,  giving  the  vine  the  form  of  a  small 
shrub.  In  the  latter  the  arms  are  scattered  uniformly  along  the 
greater  part  of  a  comparatively  long  trunk  which  in  some  forms  gives 
the  vine  or  the  row  of  vines  some  resemblance  to  a  stretched  rope  or 
' '  cordon. ' '  Various  forms  of  cordons  are  used,  differing  in  the  shape 
and  direction  of  the  elongated  trunk. 

In  the  vertical  cordon,  the  trunk  is  upright.  This  is  an  unsatis- 
factory form  because  it  is  impracticable  to  make  the  trunk  more  than 
about  five  feet  long  and  it  is  difficult  or  impossible  to  maintain  the 
arms  along  the  trunk.  The  lower  arms  tend  to  weaken  and  finally 
die  owing  to  the  shade  cast  by  the  growth  from  the  upper  arms  and 
to  the  tendency  of  the  growth  of  the  vine  to  go  principally  to  the 
highest  point.  This  is  the  only  form  of  cordon  that  has  been  much 
used  in  California  and  is  the  commonest  form  of  pruning  adopted 
for  the  Emperor.  All  the  old  Emperor  vines  pruned  in  this  way 
have  lost  the  "cordon"  character  with  all  its  advantages  and  have 
become  simply  high  "headed"  vines. 

In  the  bilateral  horizontal  cordon,  the  trunk  rises  vertically  for 
2  to  3  feet  and  then  divides  into  two  branches  which  spread  hori- 
zontally in  opposite  directions  for  3,  4,  or  more  feet.  The  vertical 
part  of  the  trunk  is  kept  bare  and  the  arms  are  distributed  every 
8  or  10  inches  along  the  upper  side  of  the  branches.     This  system  is 


2  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

preferable  to  the  last  but  is  somewhat  difficult  to  establish  and  to 
maintain  in  good  condition  and  is  inferior  to  the  next  in  most  cases. 
It  is  used  in  modified  and  incomplete  forms  in  a  few  California  vine- 
yards. 

In  the  unilateral  horizontal  cordon,  the  trunk  rises  in  a  quarter 
circle  from  the  ground  to  a  height  of  from  2  to  3  feet  and  then  extends 
horizontally  6,  7,  or  8  feet  until  it  reaches  the  upper  part  of  the  bend 
of  the  next  vine.  The  curved  part  of  the  trunk  is  kept  bare  and  the 
arms  are  distributed  every  8  or  10  inches  along  the  upper  side  of 
the  horizontal  portion.  This  is  the  system  most  commonly  used  in 
Europe  and  it  has  been  adopted  lately  by  several  growers  in  Califor- 
nia. It  has  given  good  results  with  Emperor  and,  in  experiment 
vineyards,  with  several  other  varieties,  including  the  Cornichon, 
Ohanez,  Zabalkanski,  and  Malaga,  and  it  is  recommended  in  prefer- 
ence to  either  of  the  other  two  systems  mentioned. 

This  is  the  only  system  to  be  described  here.  It  is  used  extensively 
in  Algeria.  It  has  been  in  use  to  a  limited  extent  in  California  for 
over  30  years.  Here,  however,  it  has  not  been  very  satisfactory ;  both 
because  it  has  not  usually  been  carried  out  very  skillfully  and  because 
it  has  been  used  for  varieties  and  in  districts  to  which  it  is  not  suited. 

Uses.  The  cordon  system  is  most  suitable  for  vigorous  varieties 
of  table  grapes  growing  in  rich  soil  in  the  warmer  districts. 

Some  vigorous  varieties  will  not  bear  well  when  reduced  to  the  size 
and  shape  of  a  small  shrub.  They  require  extension  in  the  direction 
of  the  natural  form  of  the  vine,  which  is  a  far  extending,  climbing 
plant.  Most  of  our  table  grapes  have  large  bunches  and  large  berries 
which  do  not  ripen  or  color  well,  nor  evenly,  when  massed  together 
as  they  are  in  most  forms  of  ' '  head ' '  pruning.  They  are  also  difficult 
to  harvest  when  in  this  condition  without  much  rough  handling,  which 
spoils  their  bloom,  breaks  many  berries  and  injures  their  appearance 
and  keeping  qualities.  The  difficulty  is  much  decreased  by  the  hori- 
zontal cordon  system. 

Disadvantages. — The  proper  training  of  cordon  vines  requires  more 
careful  and  skilled  hand  work  during  the  second,  third,  and  fourth 
year  than  most  forms  of  head  pruning.  However,  when  the  cordons 
are  established,  by  the  fifth  year,  the  pruning  is  perhaps  as  simple  as 
that  of  any  system. 

If  the  system  is  not  carried  out  skillfully  and  carefully  with  a 
full  knowledge  of  the  proper  methods,  the  vines  may  get  into  a  con- 


Circular  229]  CORDON  PRUNING  3 

dition  which  is  worse  than  is  likely  with  other  systems.  However, 
there  is  nothing  very  difficult  to  understand  or  to  do  in  properly 
establishing  a  cordon,  but  the  grower  must  be  sure  he  understands 
the  method  and  be  prepared  to  do  all  that  it  requires  if  he  is  to 
make  it  a  success.      — 


ESTABLISHMENT 

Plan  of  the  vineyard. — As  cordons  should  be  used  only  with  very 
vigorous  varieties  growing  in  rich  soil,  the  vines  should  be  given 
abundant  room.  A  suitable  spacing  is  7  feet  by  14  feet.  The  14  feet 
between  the  rows  facilitates  cultivation,  irrigation  and  the  hauling 
out  of  the  crop.  The  7  feet  between  the  vines  gives  trunks  about  10  or 
11  feet  long  of  which  7  feet  is  horizontal  and  supplied  with  bearing 
arms.  Each  vine  will  have  98  square  feet  of  soil  which  is  about  right 
for  a  large  vigorous  plant. 

Direction  of  the  cordons. — In  determining  the  direction  of  the  cor- 
dons, the  slope  of  the  land,  the  prevailing  winds  and  the  effect  of  the 
sun  should  be  considered.  The  most  perfect  conditions  are  where 
the  cordons  can  be  run  towards  the  south  and  in  the  direction  of  the 
irrigation  and  of  the  prevailing  winds.  As  all  these  conditions  can- 
not often  be  made  to  coincide,  the  best  compromise  possible  should  be 
made.  None  of  these  conditions  is  absolutely  necessary  but  all  are 
desirable.  In  most  cases  in  the  great  valleys  a  north-to-south  direc- 
tion is  the  best  compromise,  but  it  may  be  necessary  to  run  the  rows 
from  west  to  east  if  the  irrigation  water  cannot  be  made  to  flow  in 
the  other  direction. 


THE    FIRST    YEAR 

The  first  year,  as  with  any  system,  the  best  and  most  rapid  results 
are  to  be  obtained  only  by  thorough  preparation  of  the  soil  and  by 
the  use  of  first-class  planting  stock,  properly  handled.  No  stakes  are 
necessary  and  no  summer  pruning  or  disbudding  of  any  kind  should 
be  practiced.  Every  effort  should  be  used  to  stimulate  a  large  growth 
by  thorough  cultivation  and  timely  irrigation.  The  growth  should 
be  principally  early  in  the  season  and  should  slacken  in  August  and 
September.  By  October  the  canes  should  be  brown  and  well  ripened, 
all  the  leaves  mature  and  dark  green  and  there  should  be  no  light 


4  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

yellowish-green  growing  tips.  If  the  vines  are  making  new  growth 
late  in  October  or  in  November  the  wood  will  not  mature  when  the 
cold  weather  comes  and  may  be  killed  by  an  autumn  frost.  The  vines 
should  make  a  growth  of  several  canes  of  from  2  to  6  feet,  the  first 
year  and  a  correspondingly  large  root  system.     (See  Fig.  IB.) 


Fig.  1. — A.  Top  of  young  rooting  directly  after  planting.  B.  Young  vine 
after  the  fall  of  leaves.  An  average  growth  during  the  first  season,  c  o  c.  Places 
where  cuts  are  made  in  the  first  winter  pruning.  C.  Top  of  young  vine  after  the 
first  winter  pruning. 


THE    SECOND   YEAR 

Winter  pruning. — In  December  or  January,  after  the  fall  of  the 
leaves,  the  vines  should  be  pruned.  Pruning  consists  in  removing 
every  cane  but  one  with  a  pair  of  sharp  pruning  shears,  taking  care 
to  cut  as  close  as  is  possible  without  cutting  into^the  main  part  of 
the  vine.  The  cane  left  should  be  shortened  to  two  buds  (see  Fig.  1(7) 
unless  it  is  very  large,  in  which  case  it  is  better  left  as  long  as  it  is 
thick  (%  an  inch)  and  mature.     (See  Fig.  8b.) 

Trellising. — As  soon  as  the  vines  are  pruned,  the  trellis  should  be 
put  up.    An  economical  and  efficient  form  of  trellis  is  shown  in  figure  2. 

A  post  is  first  put  in  at  each  end  of  each  row.  If  the  row  is  more 
than  200  to  250  feet  long  an  extra  post  will  be  needed  in  the  middle. 
An  ordinary  split  redwood  fence  post,  5"  X  7"  or  4"  X  5"  and  7  feet 
long,  is  best.  It  should  be  placed  with  exactly  44  inches  above  the 
ground.  This  is  most  easily  and  accurately  done  by  means  of  a 
post-hole  digger.  The  posts  should  be  well  lined  up  and  firmly 
tamped.  At  the  end  of  the  row  from  which  the  cordons  run,  the  post 
should  be  3  inches  away  from  the  vine.  At  the  other  end  the  post 
should  stand  10  feet  beyond  the  last  vine.    To  allow  a  proper  turning 


Circular  229] 


CORDON  PRUNING 


space,  therefore,  the  vine  at  one  end  of  the  row  should  be  10  feet 
farther  from  the  fence  or  limit  of  the  vineyard  than  at  the  other. 

A  No.  11  smooth  galvanized  iron  fencing  wire  should  then  be 
stretched  between  the  two  posts  at  30  inches  from  the  ground,  leaving 
a  loop  or  double  wire  of  about  4  or  5  feet  at  each  end. 

Grape  stakes  are  then  driven  close  to  every  second  vine  on  the 
side  away  from  which  the  cordons  are  to  run.  Five-foot  grape  stakes 
are  exactly  the  right  length  and  should  be  driven  18  inches  into  the 
ground,  leaving  exactly  42  inches  above.  Six-foot  stakes  can  be  used 
and  driven  a  little  deeper.  The  wire  is  then  stapled  on  these  stakes 
at  exactly  30  inches  from  the  soil.  The  staples  should  not  be  driven 
in  tight  but  left  just  loose  enough  to  allow  the  wires  to  slip  through 
when  it  is  tightened.  If  the  wire  has  been  stretched  properly,  it  will 
not  require  tightening  until  the  next  year. 


T  I 

If, 


10 


E= 


r \r ■ WW 

%L —M. |p- — : '  r  U 


G5   V 


Fig.  2. — Form  of  trellis  suitable  for  a  cordon  vineyard.  FP.  Straining  end 
posts.  GS.  Five-foot  grape  stakes  at  every  second  vine.  P.  Forty-inch  redwood 
picket  at  the  intermediate  vines.  Height  of  lower  wire  30  inches,  height  of  upper 
wire  42  inches. 


A  redwood  picket,  1"  X  1"  X  40",  is  then  placed  by  each  vine 
unprovided  with  a  stake.  This  picket  should  be  driven  6  or  7  inches 
into  the  ground,  leaving  3  or  4  inches  above  the  wire  to  which  it  is 
tied  or  stapled. 

Another  wire  of  the  same  kind  but  of  No.  13  gauge  is  then  stretched 
at  12  inches  above  the  first.  This  wire  will  be  just  2  inches  below  the 
top  of  the  end  posts  and,  if  5-foot  stakes  have  been  used,  on  top  of  the 
stakes.  If  6-foot  stakes  have  been  used  the  wire  must  be  stapled  to 
the  side  like  the  first  wire.  The  putting  up  of  this  second  wire  can 
be  deferred  until  the  next  year,  but  is  best  put  up  at  this  time, 
especially  where  the  vines  are  making  a  very  strong  growth. 

It  is  very  important  for  the  regularity  and  appearance  of  the 
vineyard  that  this  trellis  should  be  put  up  straight  and  even,     A 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


,T> 


/» 


X 


so 


simple  guide  (Fig.  3)  can  be  made  that 
much  simplifies  the  placing  of  the  wires  and 
the  driving  of  the  stakes  to  exactly  the  same 
height.  This  guide  consists  of  a  piece  of 
1"  X  3"  batten,  42  inches  long,  with  a  cross 
piece  15  inches  long  nailed  across  the  bot- 
tom and  a  nail  driven  into  one  edge  at  12 
inches  from  the  top.  (The  figure  is  incor- 
rect. The  nail  should  be  30  inches  from  the 
bottom  of  the  cross  piece.) 

Disbudding  and  tying. — This  important 
operation  is  often  done  improperly  and  too 
late.  As  soon  as  the  young  vines  start  to 
grow,  they  should  be  watched  carefully  and 
before  any  have  shoots  more  than  4  inches 
long  all  shoots  and  swollen  buds  should  be 
rubbed  off  except  the  longest  and  strongest 
one  on  each  vine. 

No  shoot  longer  than  4  inches  will  be 
removed  and  most  of  them  will  be  less  than 
1  inch.  It  will  be  necessary  to  go  over  the 
vineyard  about  twice  for  this  first  disbud- 
ding. 

Tying  to  the  picket. — The  effect  of  this 

reduction  of  the  shoots  to  one  on  each  vine 

will  be  that  the  one  left  will  grow  rapidly. 

(N.B. — This  result  is  obtained  only  if  the  buds  and  shoots  removed 

are  very  small.      If  they  are  6,  8,  or  10  inches  long  when  removed, 

their  loss  stunts  the  vine  and  the  shoot  left  may  make  less  growth 

than  if  no  disbudding  had  been  done.) 

In  the  course  of  a  few  weeks,  the  reserved  shoot  will  have  grown 
12  to  15  inches  and  must  then  be  tied  loosely  to  the  picket  or  stake. 
When  this  is  done,  all  new  shoots  which  have  started  should  be 
removed.  (Fig.  4B.)  This  is  usually  the  last  disbudding  that  is 
needed  or  advisable.  If  extra  shoots  start  after  this  they  should  be 
left  but,  if  large,  should  be  limited  in  their  growth  by  pinching  off 
1  inch  of  the  growing  tip.  (Fig.  5c.)  This  will  be  sufficient  to 
prevent  their  becoming  unduly  large  and  robbing  the  main  shoot,  and 
their  leaves  will  feed  and  strengthen  the  vine. 


:Z. 


©  e 


Fig.  3. — Guide  for  insuring 
correct  height  of  wires. 


Circular  229] 


CORDON   PRUNING 


In  tying  the  growing  shoots,  the  string  should  not  be  drawn  tight. 
There  should  be  space  enough  between  the  string  and  the  shoot  to 
insert  a  finger  after  tying.  If  this  is  neglected  the  canes  will  be 
girdled  and  all  the  work  of  this  season  wasted. 

The  reserved  shoots  about  this  time — May  to  June — will  commence 
to  grow  rapidly.  About  the  time  they  reach  the  bottom  wire  they 
should  be  tied  again  higher  up.     (Fig.  4(7.) 


Ara%**rr~->r-t4 


Fig.  4. — Growth  of  v 
shoots  at  c  o  ("disbudd 
superfluous  shoots  c.     C. 


ne  during  the  second  summer.  A.  Removal  of  superfluous 
ng").  B.  First  tying  and  removal  of  second  growth  of 
Second  tying. 


Tying  to  the  lower  wire. — When  the  reserved  shoot  has  reached 
about  two  or  three  feet  above  the  bottom  wire,  the  upper  string  should 
be  removed  and  the  shoot  bent  in  a  gentle  curve  to  the  wire  to  which 
it  is  then  attached  by  a  loosely  tied  string.     (Fig.  5t'.) 

As  this  shoot  increases  in  length  it  must  be  tied  again  two  or  three 
times.  (Fig.  5t".)  By  turning  the  shoot  around  the  wire  as  it  grows 
the  tying  will  be  simplified  and  less  likely  to  give  way.  The  shoot 
must  not  be  twisted  tightly  around  the  wire  or  it  will  be  difficult  to 
remove  later  without  injury.  Not  more  than  two  turns  should  be  given 
in  its  whole  length. 


8 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Production  of  laterals. — If  this  shoot  reaches  the  next  vine  by 
July  30  and  is  still  growing  vigorously  it  should  be  pinched ;  that  is, 
an  inch  of  the  growing  tip  should  be  removed.  This  will  have  the 
effect  of  stimulating  an  abundant  growth  of  strong  laterals.  (Fig.  5?.) 
None  of  these  laterals  should  be  removed.  They  feed  the  main  shoot, 
make  it  stout  and  if  they  grow  large  enough  can  be  utilized  the  next 
year  for  the  production  of  fruit  and  arms.  Laterals  which  start  from 
the  shoot  at  any  point  between  the  ground  and  the  place  where  the 
shoot  becomes  horizontal  should  be  "tipped'  when  they  are  12  to  15 
inches  long.  (Fig.  5c,  c.)  If  any  of  the  laterals  on  the  horizontal  part 
grow  long  enough  two  or  three  of  them  should  be  tied  to  the  top  wire. 
(Fig.  51.)  This  will  prevent  the  swaying  and  turning  over  of  the 
main  shoots  in  windy  weather.  None  of  the  laterals  on  the  horizontal 
part  should  be  removed  or  tipped. 


Fig.  5. — Growth  of  vine  during  the  secbnd  summer  (continued),  t'  t" '.  Places 
and  methods  of  tying  the  main  shoot  to  the  lower  wire.  I.  Supporting  lateral  tied 
to  the  upper  wire,     c  c.  Low  growing  laterals  tipped  to  diminish  growth. 


All  suckers  from  below  ground  and  from  the  old  wood  of  the 
previous  year  should  be  kept  off.  The  smaller  they  are  when  removed, 
the  less  their  removal  will  restrict  the  growth  of  the  vine. 

Danger  of  late  growth. — There  is  great  danger  in  the  second  year 
of  the  vines  growing  too  late.  If  they  are. still  growing  strongly  in 
late  October  they  may  be  killed  by  an  early  frost.  Even  when  frosts 
do  not  occur,  the  weather  may  become  too  cool  for  the  shoots  to  ripen 
and  harden  and  they  may  be  injured  by  winter  frosts  or  fail  to  grow 
in  the  spirng  on  account  of  a  lack  of  reserve  food.  The  canes  should 
be  hard  and  brown,  the  buds  plump  and  firm,  and  the  leaves  com- 
mencing to  turn  yellow  while  the  weather  is  still  warm  in  October. 
By  judicious  management  of  the  irrigation  this  can  usually  be  brought 
about. 


Circular  229] 


CORDON  PRUNING 


THE    THIRD    YEAR 

A  well-grown  vine  at  the  end  of  the  second  growing  season,  after 
the  leaves  have  fallen,  will  consist  of  a  single  cane  extending  from  the 
ground  in  a  gentle  curve  to  the  upper  wire,  then  horizontally  along 
this  wire  to  the  next  vine  and  then  on  for  several  feet.  This  cane  will 
usually  be  supplied  with  several  or  many  laterals  of  various  sizes  and 
lengths. 

Winter  pruning. — Such  a  vine  is  pruned  by  cutting  off  the  end 
of  the  cane  at  the  point  where  it  reaches  the  top  of  the  curve  of  the 
next  vine.  (See  fig.  8a.)  Where  the  cane  is  cut  it  should  be  at 
least  Ys  of  an  inch  thick,  firm,  well  ripened  and  supplied  with  large, 
firm,  well  developed  buds. 

Canes  which  do  not  meet  these  specifications  must  be  cut  back 
shorter.  It  is  better  to  cut  them  back  too  much  than  not  enough. 
Thus,  on  some  vines  the  cane  after  pruning  will  extend  the  complete 
length  of  the  cordon,  some  will  extend  %,  %,  or  %  of  the  way  and 
some  it  may  be  necessary  to  cut  back  to  or  below  the  bend.  In  any 
case,  nothing  should  be  left  but  vigorous  healthy,  well-grown  wood. 
The  cane  should  be  cut  so  as  to  leave  the  swelling  at  the  end  of 
the  first  joint  but  not  the  bud.  This  is  for  convenience  of  tying. 
(Fig.  6.) 

'h 


Fig.  6. — Method  of  tying  cane  to  lower  wire.  a.  End  of  cane  pruned  so  as  to 
remove  the  bud  but  to  leave  the  enlargement,  b.  Firm  tie  between  the  enlargement 
and  the  last  bud  e.    o.  Loose  tie  in  all  places  except  the  end  of  the  cane. 


If  the  laterals  are  small  they  should  be  removed  completely.  If 
any  are  as  large  as  a  pencil  or  larger,  one,  two,  or  three  of  them  should 
be  left  long  enough  to  reach  to  the  top  wire.     (Fig.  81.) 

Tying. — The  vines  are  then  ready  to  tie  to  the  wire.  If  this  is 
done  properly  much  future  trouble  will  be  avoided.  (See  Figs.  6 
arid  8.)  The  end  of  the  cane  is  tied  firmly  to  the  wire  by  means  of 
a  clove  hitch  (Fig.  6b)  or  other  secure  knot.  This  tie  should  be  placed 
between  the  swelling  left  at  the  end  of  the  cane  (Fig.  6a)  and  the 
end  bud.  (Fig.  6e.)  No  tie  should  be  drawn  tight  below  a  bud.  The 
cane  should  then  be  given  the  proper  shape  and  direction  by  several 
ties  between  the  end  and  the  curve.  (Fig.  8.)  These  ties  should 
be  loose  enough  to  allow  for  the  growth  of  the  cane.     (Fig.  6c.)     If 


10 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


there  are  any  strong  laterals  one  or  two  may  be  left  long  enough  to 
reach  to  the  top  wire  and  tied  firmly.  (Fig.  SI.)  This  will  help  to 
keep  the  cane  in  place  and  prevent  its  turning  over  as  described  later. 
All  buds  should  be  removed  from  these  laterals.  This  is  most  easily 
done  in  the  spring  when  they  start.  At  that  time  they  can  be  rubbed 
off  with  the  hand. 


Fig.  7. — Growth  of  vine  during  the  third  summer,  c  c.  Shoots  on  lower  side 
of  cane  tipped  to  diminish  growth,  c'.  Extra  vigorous  shoot  on  upper  side  of  cane 
pinched  to  equalize  its  growth  with  that  of  the  slower  or  less  vigorous  shoots. 

Summer  treatment. — During  the  third  growing  season  the  cane 
that  has  been  tied  to  the  lower  wire  (Fig.  7)  develops  into  a  permanent 
trunk.  On  this  trunk  grow  shoots  which  develop  into  canes  from 
which  the  spurs  of  the  next  year  and  the  permanent  arms  are  formed. 
A  considerable  crop  should  be  obtained  this  year. 

During  this  year  there  is  great  danger  of  spoiling  the  cordon  unless 
the  work  is  done  properly.  Each  eye  of  the  cane  may  grow  and 
produce  one  or  more  shoots.  Nearly  every  one  of  these  shoots  may 
bear  one  or  two  bunches  of  grapes.  A  strong  cordon  during  the  third 
year  may  produce  more  than  20  fruit-bearing  shoots,  and  30  to  40 
flower  clusters.  If  all  these  develop  into  bunches  of  grapes  the  vine 
will  be  incapable  of  properly  nourishing  them.  They  are  likely  to 
be  small,  poorly  colored,  late  in  ripening,  and  inferior  in  sugar  and 
flavor.  Moreover,  the  vine  may  be  so  weakened  in  the  attempt  to 
bear  this  large  crop  that  it  may  be  dwarfed  for  one  or  two  years  and 
the  production  of  paying  crops  may  be  much  delayed. 

To  avoid  this  danger  only  as  many  bunches  should  be  allowed  to 
develop  as  the  vine  is  capable  of  bringing  to  perfection  and  means 
should  be  used  to  encourage  strong  growth  in  the  shoots  which  are 
to  form  the  spurs  and  produce  the  crop  of  the  following  year. 


Circular  229]  CORDON  PRUNING  11 

Another  serious  danger  is  that  all  shoots  will  be  on  the  underside 
of  the  cordon.  This  will  injure  the  bunches  by  bringing  them  into 
contact  with  the  soil  and  they  will  be  too  much  shaded  to  color  well. 
A  worse,  because  a  more  permanent  defect,  will  be  that  all  the  new 
wood  will  be  on  the  under  side  of  the  trunk  at  the  next  winter  prun- 
ing. The  upper  side  of  the  trunk  will  be  bare  and  exposed  to  sun- 
burn and  it  will  be  impossible  to  develop  strong  upright  arms  on  the 
top  of  the  trunk  where  they  ought  to  be. 

All  these  dangers  may  be  avoided  by  proper  attention  to  the  vines 
during  the  third  spring  and  summer.     (See  Fig.  7.) 

As  the  buds  start  and  grow  in  spring,  the  vineyard  should  be  gone 
over  two  or  three  times.  All  buds  within  20  to  24  inches  of  the  ground 
should  be  rubbed  off  before  they  have  grown  more  than  one  or  two 
inches.  All  other  buds  should  be  allowed  to  grow  until  they  have 
formed  shoots  at  least  8  to  10  inches  long.  At  this  time  the  shoots 
from  which  it  is  desired  to  develop  arms  should  be  chosen.  All  others 
should  be  "pinched,'  that  is,  one  inch  of  the  growing  tip  removed 
with  the  thumb  and  finger.  (See  Fig.  Iccc.)  As  a  rule  only  shoots 
on  the  lower  side  of  the  cane  should  be  pinched.  This  will  tend  to 
divert  the  growth  into  the  canes  on  the  upper  side  which  it  is  desired 
to  have  grow  strong. 

As  the  shoots  grow  long  enough,  two  or  three  of  the  strongest  on 
the  upper  side  of  the  cane  should  be  tied  to  the  upper  wire.  (See 
Fig.  7.)  This  will  insure  their  remaining  in  that  position  and  they 
will  serve  for  supports  for  the  other  shoots  which  will  attach  themselves 
to  them  by  their  tendrils.  In  this  way  the  grapes  will  be  kept  off  the 
ground  and  the  growth  will  be  on  top  where  it  is  required  for  the 
winter  pruning.  This  tying  must  be  done  early,  before  the  shoots 
have  commenced  to  bend  over  by  their  weight  or  by  that  of  their 
grapes. 

After  the  grapes  have  set  and  grown  to  the  size  of  small  peas,  it 
may  be  necessary  to  thin  them.  If  there  seem  to  be  more  bunches 
than  the  vine  can  bring  to  perfection  some  should  be  cut  off.  Where 
there  are  two  bunches  to  a  shoot  the  upper  one  may  be  removed.  If 
a  weak  shoot  is  growing  in  a  place  where  it  is  desired  to  develop  an 
arm,  the  removal  of  the  fruit  will  make  it  grow  stronger.  •  More 
bunches  should  be  left  on  large  strong  vines  and  spurs  than  on  weak. 


12  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

THE    FOURTH    YEAR 

Winter  pruning. — At  the  end  of  the  third  growing  season,  all  vines 
should  have  a  well-established  trunk.  The  largest  trunks  will  be  of 
the  full  length  of  10  feet,  reaching  the  next  vine  and  resting  on  the 
upper  part  of  its  bend.  Fig.  9.)  Others  will  extend  along  the  wire 
various  distances.     (Fig.  8b.) 

In  cases  where  the  trunk  does  not  reach  the  next  vine,  a  strong 
cane  must  be  used  to  lengthen  it.  This  cane  should  be  as  near  the 
end  of  the  trunk  as  possible  but  must  be  strong  and  well  ripened.  The 
part  of  the  trunk  beyond  where  this  cane  starts  should  be  cut  off. 
(Fig.  9p,  o.) 

All  canes  below  the  upper  part  of  the  bend  should  be  removed 
entirely.  Of  the  other  canes,  enough  of  the  strongest  should  be 
retained  to  form  spurs  about  every  8  to  10  inches  along  the  trunk. 
These  canes  should,  wherever  possible,  be  on  the  upper  side  of  the 
trunk.  All  canes  not  needed  for  this  purpose  should  be  removed. 
(Fig.  9.) 

The  canes  which  are  retained,  except  two  or  three,  should  be  cut 
back  to  spurs  of  1,  2,  3,  or  4  buds,  according  to  their  size  and  vigor. 
The  two  or  three  which  are  not  cut  back  should  be  tied  firmly  to  the 
upper  wire  (see  Fig.  9s  s)  and  these  cut  off  just  above  the  wire. 
These  are  to  help  support  the  trunk  and  to  prevent  its  turning  over 
with  the  weight  of  grapes  in  the  summer  and  autumn.  The  extra 
upper  buds  on  these  supporting  canes  should  be  removed  at  the  prun- 
ing or  as  soon  as  they  start  in  the  spring. 

Where  spring  frosts  are  feared  all  the  spurs  may  be  left  long  with 
3  or  4  extra  buds.  These  can  be  removed  in  spring  after  danger  of 
frost  is  past.  Their  presence  delays  the  starting  of  the  lower  fruit 
buds  ten  days  or  more. 

Summer  treatment. — During  the  fourth  growing  season  some  care 
will  be  necessary  to  encourage  strong  growth  on  the  spurs  that  have 
been  left  along  the  upper  side  of  the  horizontal  trunk. 

All  buds  starting  on  the  under  side  of  the  trunk  should  be  rubbed 
off  by  hand  before  they  have  grown  more  than  two  or  three  inches. 
This  will  make  it  necessary  to  go  over  the  vineyard  two  or  three  times 
during  the  spring.  Any  shoots  from  the  upper  side  or  the  spurs  which 
grow  with  extra  vigor  should  be  pinched  when  they  are  about  18  inches 
long  to  throw  more  strength  into  the  less  vigorous  shoots.     (Fig.  7c'.) 


Circular  229] 


CORDON  PRUNING 


13 


14  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Pruning  the  mature  vines. — At  the  end  of  the  fourth  growing 
season  the  cordons  should  be  complete  and  the  vines  in  condition  to 
yield  a  full  crop  the  following  year.  The  treatment  from  this  time 
is  simple  for  anyone  who  understands  the  ordinary  head  pruning. 

The  spurs  along  the  top  of  the  trunk  (Fig.  9)  will  produce  fruit 
and  canes  for  the  next  year's  pruning.  The  canes,  except  one,  from 
each  spur,  are  cut  off  at  the  winter  pruning  and  the  one  reserved  cut 
back  to  a  spur  of  one,  two  or  three  buds,  as  in  ordinary  spur  pruning. 
In  this  way  arms  are  gradually  built  up  along  the  upper  side  of  the 
trunk. 

These  arms  gradually  increase  in  length  but  much  more  slowly 
than  in  vase-formed  vines.  An  effect  of  the  cordon  system  is  to  make 
the  lower  buds  of  the  canes  more  fruitful  so  that  the  spurs  can  be 
cut  shorter.  A  vigorous  Emperor  which  requires  spurs  averaging 
4  to  5  buds  on  a  vase-formed  vine  bears  equally  well  with  spurs  of 
2  to  3  buds  on  a  cordon.  Some  varieties  which  require  2  to  3  buds 
with  ordinary  methods  will  bear  well  if  cut  back  to  a  single  bud  on 
a  cordon. 

VARIETIES    AND    CONDITIONS    SUITED    TO    CORDON    PRUNING 

1.  The  cordon  method  should  be  used  only  with  vigorous  varieties, 
growing  in  rich  soil,  abundantly  supplied  with  water. 

2.  Emperor,  Cornichon,  Ohanez,  Black  Monukka,  Zabalkanski  have 
given  better  results  with  cordons  in  our  experiments  than  with  any 
other  method  of  pruning. 

3.  Malaga,  Golden  Queen,  Molinera,  Askari,  Paykani  have  given 
as  good  results  with  cordons  as  with  any  other  method  of  pruning. 

4.  Any  very  vigorous  variety  of  table  grape  with  large  bunches  and 
berries  will  probably  give  good  results  with  this  system  where  the 
soil  and  water  conditions  are  favorable. 


STATION  PUBLICATIONS  AVAILABLE  FOR  FREE  DISTRIBUTION 

BULLETINS 


No. 
185. 

241. 
246. 
251. 

253. 

261. 
262. 

263. 
266. 

267. 
268. 
270. 


271. 
273. 

275. 

276. 

278. 
279. 
280. 

282. 

283. 
285. 
286. 
290. 

294. 
297. 
298. 
299. 
300. 
301. 


No. 
Report  of  Progress  in  Cereal  Investiga-  302. 

tions. 
Vine  Pruning  in  California,  Part  I.  304. 

Vine  Pruning  in  California,  Part  II. 
Utilization  of  the  Nitrogen  and  Organic  308. 

Matter    in    Septic    and    Imhoff    Tank 

Sludges. 
Irrigation    and    Soil    Conditions    in    the  309. 

Sierra  Nevada  Foothills,  California. 
Melaxuma  of  the  Walnut,  "Juglans  regia."  310. 

Citrus    Diseases    of    Florida    and    Cuba  312. 

Compared  with  Those  of  California.  313. 

Size  Grades  for  Ripe  Olives.  316. 

A  Spotting  of  Citrus  Fruits  Due  to  the  317. 

Action  of  Oil  Liberated  from  the  Rind.  318. 

Experiments  with  Stocks  for  Citrus.  320. 

Growing  and  Grafting  Olive  Seedlings.  321. 

A  Comparison  of  Annual  Cropping,   Bi-  322. 

ennial   Cropping,    and   Green    Manures  323. 

on  the  Yield  of  Wheat. 
Feeding  Dairy  Calves  in  California.  324. 

Preliminary  Report  on  Kearney  Vineyard 

Experimental  Drain.  325. 

The  Cultivation  of  Belladonna  in  Cali- 
fornia. 
The  Pomegranate.  326. 

Grain  Sorghums.  328. 

Irrigation  of  Rice  in  California.  329. 

Irrigation  of  Alfalfa  in  the  Sacramento  330. 

Valley.  331. 

Trials   with   California   Silage   Crops   for  332. 

Dairy  Cows.  333. 

The  Olive  Insects  of  California. 
The  Milk  Goat  in  California. 

Commercial  Fertilizers.  334. 

The    June    Drop    of    Washington    Navel 

Oranges.  335. 

Bean  Culture  in  California. 

The  Almond  in  California.  336. 

Seedless  Raisin  Grapes. 

The  Use  of  Lumber  on  California  Farms.  337. 

Commercial  Fertilizers.  338. 

California  State  Dairy  Cow  Competition, 

1916-1918. 


Control  of  Ground  Squirrels  by  the  Fumi- 
gation Method. 

A  Study  on  the  Effects  of  Freezes  on 
Citrus  in  California. 

I.  Fumigation  with  Liquid  Hydrocyanio 
Acid.  II.  Physical  and  Chemical  Pro- 
perties of  Liquid  Hydrocyanic  Acid. 

I.  The  Carob  in  California.  II.  Nutritive 
Value  of  the  Carob  Bean. 

Plum  Pollination. 

Mariout  Barley. 

Pruning  Young  Deciduous  Fruit  Trees. 

The  Kaki  or  Oriental  Persimmon. 

Selections  of  Stocks  in  Citrus  Propagation. 

The  Effects  of  Alkali  on  Citrus  Trees. 

Control  of  the  Coyote  in  California. 

Commercial  Production  of  Grape  Syrup. 

The  Evaporation  of  Grapes. 

Heavy  vs.  Light  Grain  Feeding  for  Dairy 
Cows. 

Storage  of  Perishable  Fruit  at  Freezing 
Temperatures. 

Rice  Irrigation  Measurements  and  Ex- 
periments in  Sacramento  Valley,  1914- 
1919. 

Brown  Rot  of  Apricots. 

Prune  Growing  in  California. 

A  White  Fir  Volume  Table. 

Dehydration  of  Fruits. 

Phylloxera-Resistant  Stocks. 

Walnut  Culture  in  California. 

Some  Factors  Affecting  the  Quality  of 
Ripe  Olives  Sterilized  at  High  Tem- 
peratures. 

Preliminary  Volume  Tables  for  Second- 
Growth  Redwoods. 

Cocoanut  Meal  as  a  Feed  for  Dairy  Cows 
and  Other  Livestock. 

The  Preparation  of  Nicotine  Dust  as  an 
Insecticide. 

Some  Factors  of  Dehydrater  Efficiency. 

Selection  and  Treatment  of  Waters  for 
Soraying  Purposes  with  Especial  Ref- 
erence to  Santa  Clara  Valley. 


CIRCULARS 


No.  No. 

70.  Observations    on    the    Status    of    Corn  155. 

Growing  in  California.  '  157. 

76.  Hot  Room  Callusing.  158. 

82.  The  Common  Ground  Squirrels  of  Cali-  159. 

fornia.  160. 

87.  Alfalfa.  161. 

110.  Green  Manuring  in  California.  164. 

111.  The  Use  of  Lime  and  Gypsum  on  Cali-  165. 

fornia  Soils. 

113.  Correspondence  Courses  in  Agriculture.  166. 

114.  Increasing  the  Duty  of  Water.  167. 

115.  Grafting  Vinifera  Vineyards.  168. 

126.  Spraying  for  the  Grape  Leaf  Hopper. 

127.  House  Fumigation.  169. 

128.  Insecticide  Formulas.  170 

129.  The  Control  of  Citrus  Insects. 

130.  Cabbage  Growing  in  California.  172 
135.  Official  Tests  of  Dairy  Cows.  173. 

138.  The  Silo  in  California  Agriculture.  174. 

139.  The  Generation  of  Hydrocyanic  Acid  Gas  175. 

in  Fumigation  by  Portable  Machines. 

144.  Oidium  or  Powdery  Mildew  of  the  Vine.  176. 
148.  "Lungworms." 

151.  Feeding  and  Management  of  Hogs.  177. 

152.  Some  Observations  on  the  Bulk  Handling  178. 

of  Grain  in  California.  179. 

153.  Announcement    of   the    California    State 

Dairy  Cow  Competition,  1916-18.  181. 

154.  Irrigation     Practice    in     Growing    Small  182. 

Fruits  in  California. 


Bovine  Tuberculosis. 

Control  of  the  Pear  Scab. 

Home  and  Farm  Canning. 

Agriculture  in  the  Imperial  Valley. 

Lettuce  Growing  in  California. 

Potatoes  in  California. 

Small  Fruit  Culture  in  California. 

Fundamentals    of    Sugar    Beet    Culture 

under  California  Conditions. 
The  County  Farm  Bureau. 
Feeding  Stuffs  of  Minor  Importance. 
Spraying  for  the  Control  of  Wild  Morning- 

Glory  within  the  Fog  Belt. 
The  1918  Grain  Crop. 
Fertilizing  California  Soils  for  the   1918 

Crop. 
Wheat  Culture. 

The  Construction  of  the  Wood-Hoop  Silo. 
Farm  Drainage  Methods. 
Progress   Report  on  the  Marketing  and 

Distribution  of  Milk. 
Hog  Cholera  Prevention  and  the  Serum 

Treatment. 
Grain  Sorghums. 

The  Packing  of  Apples  in  California. 
Factors  of  Importance  in  Producing  Milk 

of  Low  Bacterial  Count. 
Control  of  the  California  Ground  Squirrel. 
Extending  the  Area  of  Irrigated  Wheat  in 

California  for  1918. 


CIRCULARS — Continued 


No. 

183.  Infectious  Abortion  in  Cows. 

184.  A  Flock  of  Sheep  on  the  Farm. 

185.  Beekeeping  for  the  Fruit-grower  and  Small 

Rancher  or  Amateur. 

188.  Lambing  Sheds. 

189.  Winter  Forage  Crops. 

190.  Agriculture  Clubs  in  California. 

191.  Pruning  the  Seedless  Grapes. 

193.  A  Study  of  Farm  Labor  in  California. 
198.  Syrup  from  Sweet  Sorghum. 

201.  Helpful  Hints  to  Hog  Raisers. 

202.  County  Organizations  for  Rural  Fire  Con- 

trol. 

203.  Peat  as  a  Manure  Substitute. 

205.  Blackleg. 

206.  Jack  Cheese. 

208.  Summary  of  the  Annual  Reports  of  the 

Farm  Advisors  of  California. 

209.  The  Function  of  the  Farm  Bureau. 

210.  Suggestions  to  the  Settler  in  California. 
214.  Seed   Treatment   for   the   Prevention   of 

Cereal  Smuts. 


No. 

215.  Feeding  Dairy  Cows  in  California. 

217.  Methods    for    Marketing    Vegetables    in 

California. 

218.  Advanced  Registry  Testing  of  Dairy  Cows. 

219.  The  Present  Status  of  Alkali. 

220.  Unfermented  Fruit  Juices. 

221.  How  California  is  Helping  People  Own 

Farms  and  Rural  Homes. 

222.  Fundamental  Principles  of  Co-operation 

in  Agriculture 
223    The  Pear  Thrips. 

224.  Control  of  the  Brown  Apricot  Scale  and 

the    Italian   Pear   Scale   on   Deciduous 
Fruit  Trees. 

225.  Propagation  of  Vines. 

226.  Protection  of  Vineyards  from  Phylloxera. 

227.  Plant  Disease  and  Pest  Control. 

228.  Vineyard  Irrigation  in  Arid  Climates. 

229.  Cowdon  Priming. 

230.  Testing  Milk,  Cream,  and  Skim  Milk  for 

Butterfat. 

231.  The  Home  Vineyard. 


